Abstract: The forging model for Cold rolling is one of the rolling models which is used in rolling calculations. In this model, the final rolling pressure is an average value and it is not as accurate for actual and industrial cases. Also, by using forging model, friction hill curves are plotted due to the central point of rolling bite length while frictional stresses intersect at the neutral point of rolling bite. In this study, a new model based on the forging model is presented to determine the rolling pressure during Cold rolling process for using in a reversing tandem mill, where this is called “Improved forging model”. In the proposed model, the intersection of the frictional forces is the neutral point. Finally, the computing results from this new model coincide well with the precedent investigations.

Strip tearing during Cold rolling process has always been considered among the main concerns for steel companies, while several works have been done so far regarding the examination of this issue. In this paper, experimental data from Cold rolling tandem mill is used for detecting strip tearing. Sensors are placed across the Cold rolling tandem mill, to collect information on parameters (such as angular velocity of the rolls, voltage and the electrical current of electrical motors driving rolls, roll gap, and strip tension force between rolls) directly from the Cold rolling tandem mill. The information includes two modes: perfect rolling and ruptured rolling. A neural network is designed by means of MATLAB software and, then, trained using the information from the related data files. Finally, the neural network is examined by new data. It is concluded that the neural network has good accuracy in distinguishing between perfect and defected rolling.

The objectives in the Cold rolling process include improved sheet surface quality and enhanced steel mechanical strength. Given the increasing demand for higher steel surface quality, more rapid production, and thinner steel plates, more attention has been directed toward the parameter of temperature in Cold rolling as a means of achieving the above objectives. Due to the friction between work rolls and steel sheet caused during the Cold rolling process and because of temperature changes of the work piece during plastic work, a non-uniform temperature distribution results along the work roll axial direction which ultimately leads to improper and undesirable expansion of the work roll along its axis. This, in turn, causes an uneven work roll slide on sheet surface; hence, the uneven and wavy steel surface. In this study, we used headers with a variety of nozzles for cooling the work rolls in order to achieve uniform temperature distribution and thermal expansion of the work roll. In this method, the cooling system is applied to the work roll in such a way that the work roll gains the desired efficiency in terms of both optimized energy consumption and work roll thermal expansion.

The full annealing AA6061 aluminum alloy was subjected to severe plastic deformation via the combination of equal channel angular pressing (ECAP) and Cold rolling (CR) in order to refine its microstructure and to improve its mechanical properties. According to the results of hot and Cold tensile tests, the combination of ECAP and CR significantly affected the final strength and ductility of studied AA6061. Four passes of ECAP followed by 90% reduction in rolling led to about 5.4 and 3.15 times increase in the yield and ultimate tensile strengths, respectively. In addition, the hot ductility and strain rate sensitivity were increased by applying ECAP plus CR. The changes in mechanical properties were attributed to the enhanced dislocation density and to the reduced grain size. The results show that a decrease in grains/subgrains size (0.37 mm) and an increase in the fraction of high angle grain boundaries, exhibited significant effect on the hot ductility of higher severe plastic deformed sample.

In the present study, the influences of Cold rolling and annealing time on the fatigue crack propagation behavior of AA5052 aluminum alloy were investigated. The alloy sheet was Cold-rolled under different rolling reductions, i.e., 0, 15, 30, and 45%. 45% as-rolled specimen was then annealed at 370°C under different annealing times, i.e., for 2, 4, and 6 h. The microstructure evolutions after the Cold rolling and annealing treatments were also examined using optical microscopy whereas the fatigue crack propagation behavior was characterized by using a fatigue test. Results showed that severely elongated grains were observed with increasing the rolling reduction. The elongated microstructures were changed into equaxial structures due to recrystallization during annealing treatment. The fatigue life was decreased drastically by increasing the rolling reduction but increased significantly with increasing annealing time. The fatigue life of the alloy was reduced by 93% when Cold-rolled up to 45%. On the other hand, the fatigue life of the 45% rolled samples was increased significantly by 412% when annealed at 370ºC for 6 h.